Turbine systems are continuously being modified to increase efficiency and decrease cost. One method for increasing the efficiency of a turbine system includes increasing the operating temperature of the turbine system. To increase the temperature, the turbine system must be constructed of materials which can withstand such temperatures during continued use.
In addition to modifying component materials and coatings, one common method of increasing temperature capability of a turbine component includes the use of complex cooling channels. The complex cooling channels are often incorporated into metals and alloys used in high temperature regions of gas turbines. The complex cooling channels can be difficult to form. Casting in the channels can require complex molds that are difficult to position and control placement of near the hot gas path where cooling is required. Machining in the channels after casting then requires closing them off at the surface through methods such as brazing and/or thermal spraying of materials often inadvertently fills the complex cooling channels blocking the flow of cooling fluids, such as air from a compressor section of a gas turbine. Some designs are actually not capable of being manufactured using traditional methods due to their complexity and require use of methods such as powder bed laser sintering.
If brazing of materials to a surface of the substrate to cover the channels is performed, the brazing temperatures required to sufficiently braze the material may soften the material. The softened material can sag or droop into the complex cooling channels, blocking them as they harden. As such, brazing requires a very narrow temperature range, outside of which the component can be damaged or made unusable. In general, machining of channels can be very difficult.
If thermal spraying of coatings is performed, the sprayed materials can fill the complex cooling channels with the coating. To avoid filling the complex cooling channels, a fill and leech method can be used. The fill and leech method includes filling the complex cooling channels with a sacrificial material, coating the component and leeching the sacrificial material to form the complex cooling channels. Such methods are expensive, difficult to apply and remove, and often have a high scrap rate. Also, making miniature-sized components and features using traditional manufacturing methods exacerbates such drawbacks.
A manufacturing process, a swirling device, and a thermal management process that do not suffer from one or more of the above drawbacks would be desirable in the art.